1. Field of the Invention
The present invention relates to a display device, and more particularly, to a 2-dimensional and 3-dimensional image display device in which a color change versus a change in viewing angle is small, and a method of manufacturing the same.
2. Discussion of the Related Art
With the increasing demand for Internet, realistic communication, virtual reality and operation using an endoscope, there is an increasing need for the integration of computer, broadcasting and communication into one medium based on visualization of multimedia technology, and a 3-dimensional visualization of diagnosis and measurement results. As a result, there is an increasing need for a display device capable of displaying an image 3-dimensionally.
3-dimensional display technology is advantageous in various fields such as advertising, a home multimedia image display terminal, an image display terminal for simulation and education/training, a visualization image display terminal for precise measurement and diagnosis, a medical image display terminal, various image display terminals for watch and control, a 3-dimensional image monitor for video conferences and advertisements, a 3-dimensional television for broadcasting, an image display terminal for education/entertainment, manufacturing parts for various kinds of special environments, an image device for 3-dimensional games, and various head up displays for airplanes and vehicles.
The technologies required for a general 3-dimensional display device include the architectural design and manufacturing technologies for an optical plate, e.g., a lenticular lens plate or a microlens plate, for forming a visual field, and a drive control technology for reproducing a pixel pattern corresponding to the formation of the visual field on the display device.
Methods for displaying a 3-dimensional image is classified into two types of which one is a 2-viewpoint type and the other one is a multiple viewpoint type. The 2-viewpoint type displays respective images for left and right eyes, whereas the multiple viewpoint type display displays a binocular parallax image captured in wide variety of directions. For the multiple viewpoint type display, there is a problem where the resolution decreases in proportion to the number of viewpoints, whereas there is an advantage in that the degree of freedom of viewing position is higher so that it is possible to naturally see the 3-dimensional image.
Methods of focusing the image data for left and right eyes on the left and right eyes, respectively, include a parallax barrier method, a lenticular method or the like.
FIG. 1 is an exploded perspective view of a related art display device capable of 2-dimensional and 3-dimensional images, and FIG. 2 is a schematic view illustrating how to display the 3-dimensional image using the related art display device of FIG. 1.
Referring to FIG. 1, a liquid crystal display (LCD) device for displaying the 3-dimensional image using a parallax barrier panel 3 includes a backlight unit 1, an image display panel 5 for displaying an image by light generated from the backlight unit 1, and the parallax barrier panel 3 disposed between the backlight unit 3 and the image display panel 5, for displaying the 3-dimensional image.
The image display panel 5 includes an upper substrate on which a color filter layer is formed and a lower substrate on which a thin film transistor (TFT) as a switching device and a pixel electrode are formed, wherein a liquid crystal layer is interposed between the upper and lower substrates.
This method of displaying the 3-dimensional image using the parallax barrier panel 3 utilizes the principle of binocular parallax between left and right eyes, that makes it possible to see the image 3-dimensionally as when a human actually sees an object. Referring to FIG. 2, image data for the left eye and image data for the right eye are input into the image display panel 5 (minimally, two viewpoints). Therefore, it is possible to see the 2-dimensional image as the 3-dimensional image by intentionally focusing left and right eye images on a human's left and right eyes, respectively, by virtue of the parallax barrier panel 3.
That is, by inputting two sets of image data on a screen and making the left and right eyes separately focused on the left and right images, respectively, the 2-dimensional plane image can be perceived as a 3-dimensional image.
The parallax barrier panel 3 is divided into a plurality of barrier areas 4a for propagating the light toward a human's left eye, and a plurality of aperture areas 4b for propagating the light toward a human's right eye.
Assuming that a distance between the left and right eyes is about 65 mm and a distance within which a man can see the image ranges from 25 cm to 30 cm, for example, the parallax barrier panel 3 should be designed such that the left and right images are focused on the left and right eyes, respectively, within the distance in range of 25 cm to 30 cm apart from the image display panel 5.
However, the parallax barrier panel 3, which is used as a switch panel in the related art LCD device, uses a twistic nematic (TN) mode liquid crystal panel in which a common electrode is disposed on an upper substrate and a pixel electrode is disposed on a lower substrate generally. Thus, there are problems in that the viewing angle is quite narrow and the color change becomes large versus the viewing angle in displaying the 3-dimensional image (see FIG. 9A).
In particular, because a strict international standard spec for color uniformity exists, it is impossible to sell products if the color change becomes large.
Moreover, because a response speed of liquid crystal is slow in response to an electric field in the TN mode switching panel, it is a difficult to naturally display the 2-dimensional and 3-dimensional image according to the related art display device.